The class of shaving preparation referred to herein as a "self-foaming gel" is a lather-producing composition which is capable of being dispensed as a gel that is substantially free from foaming, but which when spread over the skin and beard produces a foam generated by the action of a volatile self-foaming agent. Such compositions generally take the form of an oil-in-water emulsion ill which the self-foaming agent, generally a low-boiling aliphatic hydrocarbon, solubilizes the oil phase, and the water phase comprises a water-soluble soap component so selected that the resulting packaged composition is in the form of a stable gel under ambient conditions.
Such products are typically packaged in an aerosol container with a barrier such as a piston or collapsible bag to separate the self-foaming gel from the propellant required for expulsion and thereby ensure that a homogeneous gel is dispensed, substantially free of bubbles, which can produce a self-generated lather of uniform consistency and density throughout the life of the product. Other known packaging forms for self-foaming gels include conventional, i.e., non-barrier, aerosol containers and collapsible tubes, although these less expensive packages have not always been entirely satisfactory due to formulation compromises attendant with their use.
For further description of parameters involved in the formulation of such products, reference may be made, for example, to U.S. Pat. Nos. 3,541,581 and 4,528,111; typical manufacturing processes and equipment are disclosed in, for example, U.S. Pat. Nos. 4,405,489 and 4,651,503.
Self-foaming shaving gels are, as noted, well known in the art and have been commercially available for over twenty years, during which time they have achieved a substantial share of the total market for shave preparations. Users tend to exhibit considerable loyalty to this form of shaving preparation and associate its use with obtaining a close, comfortable shave. Nevertheless, further improvements in performance would be desirable.